7474 Alloy20

The first version of alloy 20 was introduced in 1951 for sulfuric acid applications. A few years later, a columbium-stablized version was developed as 20Cb3, which allowed its weldments to be used in the as-welded condition without the need for postweld heat treatment. Further modifications led to the modern version alloy 20Cb3 with increased nickel content. This alloy is used in many applications due to its good resistance in sulfuric acid media and resistance to stress corrosion cracking. It is used in the manufacture of synthetic rubber, high octane gasolene, solvents, explosives, plastics, synthetic fibers, chemicals and pharmaceuticals, in the food processing industry, and many others. However, due to its lower molybdenum content, the localized corrosion resistance of this alloy